This invention relates to visual improvements to Sense Through The Wall (STTW) radar displays. In the post 9-11 era, there is a growing need for STTW technologies to support urban combat, Special Forces, tactical entry, homeland security, law enforcement, fire protection, and search and rescue. While STTW systems have evolved during the past decade, these platforms are struggling to achieve market penetration in spite of an extreme demand for the technology. One of the largest barriers to widespread acceptance of STTW systems is the accompanying burden of expertise, focus, and response time that is needed to interpret the graphical user interfaces that are currently presented to practitioners of the technology. The method disclosed herein causes a computer, embedded microprocessor, and the like to employ the output results of STTW radar signal classification algorithms to select and display an image that represents the target that is detected on the opposite side of any visual barrier. In an optimal embodiment of this invention, the method further causes the foregoing electronic hardware or software to superimpose a target image over a live video stream of the area in front of the radar. This approach supersedes the blob-like, wiggle plot, and radar speckle images like those that commonly used by evolving STTW systems; examples of these displays are shown in FIGS. 1 through 3.
The quest of providing easy to understand radar visual displays has been an on-going challenge since the infancy of radar in the 1940's. Early radar displays comprised blob-like images that while difficult to interpret are still in common use in both STTW and non-STTW platforms. One of the earliest overlay radar displays, which employs etched optics to superimpose fictitious terrain data over a CRT radar screen, was disclosed by Bomzer in 1961 under U.S. Pat. No. 2,984,915. His invention, which was designed primarily for training purposes, enabled realistic radar scenes of urban areas to be superimposed over ambient displays of radar training data. The method provides trainees with a realistic visual of radar targets and background clutter from simulated data. Balding also patented a simulation support device in 1966 under U.S. Pat. No. 3,229,018 that overlays e-scope and terrain clearance data to provide a simulated scan on a map film slide made up of contour levels of varying transparency with each shade representing a different elevation. A radar display scheme that employs electronic hardware to provide similar elevation data of landmass radar on a live display was patented by Marrero under U.S. Pat. No. 3,413,402 in 1968. The principal object of Marreo's system is to provide a means for storing and recovering elevation data in such a manner that it alleviates some of the display limitations of prior art. Other relevant prior art, filed under U.S. Pat. No. 4,384,286 on May 17, 1983 by DiToro, employs a processor to determine the appropriate position to display a detected object on a radar screen that represents the actual coordinates of the target.
Like this invention, most of the more recently dated prior art relies on methods that cause a computer, embedded processor, or other electronic hardware to optimally display a target. A generic radar display that was patented by Allen on Jul. 31, 1990 under U.S. Pat. No. 4,944,679 employs software controlled generic radar display algorithms to cause a high resolution color monitor to display radar sweep, compass rose, front panel symbology, and diagnostic information. This invention, which relates particularly to the field of simulation training devices, further provides a target generator that displays simulated target information in a standard Plan Position Indicator format. On Apr. 1, 1997 Logg was awarded U.S. Pat. No. 5,616,031 for a system and method of shadowing an object in motion to be used in a helicopter flight simulator having improvements in visual cues and modeling. On Dec. 16, 1997 Brown was awarded U.S. Pat. No. 5,699,067, which discloses a high capacity complex radar plot display with low CPU loading. The invention includes a display process that causes a graphics window server to render “walking worm” animation a display console. The animation comprises a chain of symbols that represent the current and several of the past positions of the target. An endless loop causes the most current symbol to be plotted and the most dated symbol (or target position) to be erased; the resulting moving target history is iteratively displayed in an endless loop to render the animation.
There is an abundant volume of prior art that employs symbol overlay techniques to present complex data or user interface menus to an end-user. On May 21, 1996 Smalanskas et al. obtained U.S. Pat. No. 5,519,410 for a virtual image display management system with a heads-up display to enable the operator of an automobile or other equipment to focus on primary functions, such as vehicle operation, while providing secondary information within the operator's primary visual field; without requiring the operator to refocus. Like the present invention, Smalanskas employs several secondary functions that display combinations of analog/digital symbology, icon representation, target silhouette representation, alphanumeric text, and static or motion picture format. In a separate disclosure Bertram patented two video receiver displays in February 1997 that use software algorithms to cause interactive images of a menu system to overlay live television video under U.S. Pat. Nos. 5,602,597 and 5,606,374. Betram's approach combines a video display, which may be a television receiver with associated set top device, an intelligent television receiver, or a personal computer system enabled for television display, and a remote control which controls modification of the visual images displayed. His invention also includes cooperative display controller and video reception circuitry that causes full motion video visual images to occupy substantially the entirety of a viewable screen area and an overlying menu display to occupy a minor portion of the screen area over the full motion video.
Other image overlaying prior art includes an image displaying apparatus that was patented by Kanada et al. in U.S. Pat. No. 5,550,560 on Aug. 27, 1996. In this disclosure Kanada describes a system and method for detecting when an operator selects one of multiple objects from a projected image. Image data, object data and relative position data are used to cause a liquid crystal display screen to display a composite of both image and objects. When the operator presses a switch, a signal including the state of brightness from an optical sensor is entered into a brightness determinator of a personal computer.
While prior art adequately describes methods to display user interface data and symbols or icons that represent a target on LCD panels, PDA devices, VGA displays, helmet mounted displays, and any other type of display, even the state of the art lacks a method that specifically enables STTW platforms to convey complex radar data in a format that is easy to understand. Consequently, the state of the art presents complex visual displays like those that are shown in FIGS. 1 through 4, which tend to distract practitioners of the technology from the focus of their mission. Prior art and the state of the art fail in particular to use or describe a method or device that combines Sense-Through-The-Wall (STTW) radar data interpretation such as autocorrelation, statistical classification, biology modeled classifiers, and the like with 1D, 2D, and 3D graphical methods that present easily recognizable images to represent target information that is based on the composition of the detected target. A principle objective of this invention is to incorporate the foregoing into STTW systems so that the ease of using of the evolving technology is sufficient to foster widespread market acceptance by practitioners of the same.